diff options
author | Jeff Muizelaar <jrmuizel@gmail.com> | 2021-08-11 16:15:11 -0400 |
---|---|---|
committer | GitHub <noreply@github.com> | 2021-08-11 16:15:11 -0400 |
commit | 7b359e1939ff642cbb28d8653fbfa2e337debef8 (patch) | |
tree | c6cf726f70476da9cf946e87637ad851eb8f01b9 | |
parent | 6f04b2f2214f72d24d1036a19b3ca3b9baec38ff (diff) |
lwriter.cpp: Elaborate the documentation of some of the VIA pins (#8423)
-rw-r--r-- | src/mame/drivers/lwriter.cpp | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/src/mame/drivers/lwriter.cpp b/src/mame/drivers/lwriter.cpp index 7cdeb199ea5..a19b49f58fa 100644 --- a/src/mame/drivers/lwriter.cpp +++ b/src/mame/drivers/lwriter.cpp @@ -378,7 +378,7 @@ void lwriter_state::fifo_out_w(uint8_t data) * 1 - print sbsy * 2 - ? * 3 - ? - * 4 - some print thing + * 4 - print vsreq * 5 - switch setting low * 6 - switch setting high * 7 - print (STATUS/COMMAND Message Line) @@ -411,13 +411,23 @@ WRITE_LINE_MEMBER(lwriter_state::via_ca2_w) logerror(" VIA: CA2 written with %d!\n", state); } +/* via port b bits: + * 0 - ? + * 1 - print rdy + * 2 - print pprdy + * 3 - overlay + * 4 - + * 5 - + * 6 - timer 2 clk + * 7 - print related timing thing + */ uint8_t lwriter_state::via_pb_r() { logerror(" VIA: Port B read!\n"); return 0xFB; } -// The 3rd bit is used for talking with the print controller +// The 3rd bit (PPRDY) is used for talking with the print controller // and is inverted on II NT uint8_t lwriter_state::via_pb_lw2nt_r() { |